These are the electronic devices that i use on my extended hikes on the appalacian trail. I had been using a device that allows me to transfer power from AA batteries to any device that will accept a USB/firewire/plugs in. However, this requires me to carry 7-8 AA batteries in my pack and i don't like the expense of always buying batteries or the waste.

Is there a solar charging system that i can use to power the three devices i listed above? Here are my requirements for the device by importance:

I'm preparing for a 480 mile thru-hike of the Colorado Trail myself next summer and just got done reading Andrew Skurka's book (which I highly recommend, along with his blog). As a result, I'm a complete gram weenie. After doing my research I'm leaning more toward a USB battery like this if in needed AA batteries, I'd use with one of these usb chargers.

Here's my logic. I'm going to be on the move, at least 1/2 of the time in heavy trees or facing the wrong direction for good sunlight to fall on the panel on my back. I'm going to be moving 8-10 hours a day. Most of the solar chargers are marginal at best and will fully charge a cell phone in 8-13 hours of continuous sunlight. They weigh, at the lightest 12 oz. and most are somewhere north of a pound and most cost about $90-130.

One 10000 mah usb charger will hold about 4-5 full charges for my cell phone. It weights 10 oz. It's half the price ($50). I'm going to be stopping in town for food at least every five days, so I can charge it while in town or buy two and ship them home for recharging and get them shipped to me along the trail. I won't have to worry about cloudy days, tree cover, or walking in the wrong direction. There are larger capacity units available as well as smaller, cheaper units (this one just gets exceptionally good reviews).

I know it's not the 100% off the grid solution, but I'm convinced that the off the grid solutions are so marginal for a backpacker that they're not realistic. If I was sitting in camp for eight hours a day I might risk it, but on the trail I just don't think solar is the solution.

Another thing to note is that the Spot needs Lithium batteries to work right and reliably. Given that a set of lithiums will last 14 days with the tracking on, I would just stick to lithiums.

For headlamps, I'm moving away from a dedicated headlamp and toward the Fenix LD 01 flashlight with the reversible clip so it will go on the brim of your hat (warning, there are multiple versions of this light, some put out more light, but are less efficient). It weighs in at 14 grams (without the one AAA battery), which will last up to 27 hours on low (which is adequate to read by), but can also put out 27 lumens (enough to hike by in most terrain) for just over three hours or put out a serious 72 lumens for 90 minutes. That's on one single 11.5 gram AAA battery.

I have a steripen and if I were going with rechargeable batteries, I'd go with the CR123 unit that comes with a solar charging box (and still carry a couple new CR123 lithiums just in case). Since my last hike on the CT last summer I've moved to using a Sawyer SP121 Just Drink water filter. This is less because I'm a weight weenie and more because I drink from a hydration bladder anyway, so I find it easier and faster to just dip my bladder into any stream, do nothing to treat it, and just drink normally through my tube. While it does occasionally need to be backflushed and stored properly if you aren't using it for an extended period of time, you simply won't find a better warranty than their one million gallon guarantee. No pumping, no chemicals, no batteries, no wasted time and when you get to camp, hang your bladder in a tree and you have a gravity filter.

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I am a gram weenie myself, in the coldest months of the year im under 25lb for a week on the trail.

It's a tough decision, the angle of the sun is less direct in the winter so one could assume that solar panels would do worse in the winter. Also the AT is the green tunnel, not much sunlight getting through that canopy.

I'm currently using a device that will accept lithium ion or regular AA/AAA batteries. I don't remember how efficient it was, ie how much charge i got into my devices from the batteries, but i remember mostly chargin my iphone in a few hours. I remember the device getting hot. Its basically a little rectangular device, very light, under 4 oz, a usb/firewire/many other connections can be made to it and you just hookup whatever device you want to charge to it and drain the inserted batteries. Works, but liek i said, you have to carry around dead batteries and pay for them.

Thanks for the advice endurance and everyone else, i am well aware of how awesome the sawyers are. They really are the best. I'm currently using bleach drops and waiting 30 min, but intend to build a sawyer gravity setup soon.

Regarding charging issues, make sure whatever device you're using has different ports with different outputs. If you were charging a tablet, you need a 2a output, but for a phone, anything more than 1a is definitely going to overheat it. That's a lot of current for those smaller devices. Ideally, you'd want one that puts out 500ma, since as a rule you don't want to push in more than half the amp/hour capacity of a battery in. In other words, if your phone's battery is a 1500mah capacity, you'd want to use nothing larger than a 750ma charger. However, there are very few options that meet that criteria.

I've used pumps (first need, msr waterworks, msr miniworks), iodine and chlorine dioxide tablets, 2 steripens (one AA, one USB), and finally the Sawyer. I got Giardia in 1987 using the first need. My MSR was notorious for clogging in streams heavy in tannins and other debris. Iodine worked well, but doesn't taste good (and once you open a bottle, you really should use it up in 90-120 days because it degrades in air) (I've carried it as my backup system for years and used it dozens of times). I still carry Chlorine Dioxide as my backup system and needed it three times last year when I ran out of water on the trail. The Steripens eat batteries even when they're off at an alarming rate. Frankly, if you don't go with a rechargeable system I wouldn't rely on it without at least two extra sets of batteries. I still carry it in my travel kit because you can sit in a restaurant in Mexico and sterilize the water without looking like too big of a freak (assuming you ordered without ice).

So that's why I settled on the Sawyer. I'm not thrilled with the resistance in the tube and needed to train myself to take more small sips rather than trying to take fewer big gulps (which are all but impossible). Overall, it's worked well for me all summer and fall and now I use it even on my day hikes when near water so I can get away with carrying less. Last week I did a 14.2 mile day hike leaving the car with 34 oz. in a 50 oz. bladder. I just had to stop twice to fill it up in a stream as I hiked. It's a serious luxury.

My goal for the CT is to be around 20 pounds including food, but I'll never have a stretch longer than five days without resupply and the total trail will be 18-21 days. My wife, if she tolerates me going, will insist that I carry a Delorme InReach so I can text her, even out of cell range. That's 12 oz. of wasted weight, but given that I'm soloing I guess I don't mind too much.

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Ban shreaded cheese. Make America grate again.

Carefully consider the costs and benefits of a vegetarian diet; it could be a big missed steak.

A soldier who survives a mustard gas and a pepper spray attack is a well seasoned veteran.

+1 have this, used it backpacking and at the track works well. Comes with 4 rechargeable aa in a little back that the solar charges but you could use those batteries for anything and then still use the solar directly to your usb device. I got the kit for about $100

I haven't used this before but it seems to address the lack of direct sunlight problem. Actually it works at night just fine. Depending on the weight of your current stove plus a solar solution (such as GoalZero) this might be an outstanding compromise:

I haven't used this before but it seems to address the lack of direct sunlight problem. Actually it works at night just fine. Depending on the weight of your current stove plus a solar solution (such as GoalZero) this might be an outstanding compromise:

A couple members have reviewed these and the problem is the weight (33 ounces) and relatively low output. Unless you want to sit in camp tending a fire for five or six hours ever day, you won't be getting a full charge on your battery.

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Ban shreaded cheese. Make America grate again.

Carefully consider the costs and benefits of a vegetarian diet; it could be a big missed steak.

A soldier who survives a mustard gas and a pepper spray attack is a well seasoned veteran.